Questions tagged [superblock]
The superblock tag has no usage guidance.
78
questions
64
votes
5
answers
269k
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Recovering ext4 superblocks
Recently, my external hard drive enclosure failed (the hard drive itself powers up in another enclosure). However, as a result, it appears its EXT4 file system is corrupt.
The drive has a single ...
8
votes
1
answer
5k
views
Difference between backup superblocks
Recently I accidentally formatted an EXT4 partition to FAT. I got into a panic. After a long journey through a dark wood in which my hope was fading I could recover my partition and it seems ok. After ...
8
votes
2
answers
11k
views
Btrfs super-recover says all superblocks are good but mount disagrees
I have an external drive formatted with BTRFS that seems refuses to mount:
$ sudo mount -vs -t btrfs -o ro,recovery,errors=continue /dev/sdb2 /media/user/dir
mount: /dev/sdb2: can't read superblock
...
7
votes
1
answer
7k
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How can I dump the contents of a filesystem's superblock?
I understand that I can list the location of a filesystem's superblocks using the following commands.
Example
First get the device handle for the current directory.
$ df -h .
Filesystem ...
5
votes
3
answers
49k
views
How to fix if I received mount: /dev/vgname/lvname: can't read superblock for the local filesystem?
I received an incident when I was trying to do mount -a .
I was getting the below error. So how to fix this issue?
mount: /dev/vgname/lvname: can't read superblock
4
votes
3
answers
8k
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lost superblock in md raid
Issue on Red Hat Linux 5.
Due to some miscommunication two LUNs in our environment were enlarged from 1.2 TB to 1.7 TB.
Now, after a reboot, mdadm does not find the superblocks to build the array ...
4
votes
3
answers
11k
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Data recovery from an accidental format on ext4 partition
When I was installing Mint Debian edition unlike the classic edition, the installation automatically formated my home partition when I did not specify to format.
So the formatting previously was ext4 ...
4
votes
2
answers
14k
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Can't load Ubuntu: Superblock checksum does not match superblock while trying to open /dev/sda7
I have a problem while loading into Ubuntu 17.04.
This happens for the 2nd time after I booted into Windows. For the 1st time I just reinstalled the Ubuntu.
I am not good at this question, so I hope ...
4
votes
1
answer
4k
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mdadm - Accidentally ran "mdadm --create" on an existing raid-1. The superblock is now corrupt and I am unable to recover data. Did I bork my data?
I have /dev/sdb1 and /dev/sdc2 that were previously setup into a RAID-1 with mdadm, but then I reinstalled and lost the old configuration. Out of idiocy, I ran
sudo mdadm --create /dev/md0 --level=1 ...
4
votes
1
answer
3k
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Ext2 block structure: size of reserved GDT Blocks
In every publication I found about ext2, the structure of a block group is defined as following:
Super Block: 1 block
Group Descriptor: N blocks
Data Bitmap: 1 block
Inode Bitmap: 1 block
Inode Table:...
4
votes
3
answers
17k
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ext4 - Bad magic number in super-block
ext4 is failed me again! the most unstable fs
tried to fix it by restoring block from backup, but without luck..
↪ sudo fsck.ext4 -v /dev/sdd
e2fsck 1.45.6 (20-Mar-2020)
ext2fs_open2: Bad magic number ...
4
votes
1
answer
17k
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e2fsck: unable to set superblock flags on LogicalVolume
When I boot my machine either in normal mode or runlevel 1 it throws following error and I'm unable to boot the machine:
checking filesystems
/dev/MyGroup/LogVol00: UNEXPECTED INCONSISTENCY; RUN ...
4
votes
2
answers
2k
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Access ext4 disk that lost superblock and its backups
I found myself in a weird situation with my system's disk. It's Linux system with 3 partitions, boot, swap and filesystem (ext4). A few days ago i used knoppix from a pendrive (I made the bootable usb ...
3
votes
1
answer
7k
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How to fix BTRFS superblock error after resize/shrink (BTRFS: couldn't get super buffer head for bytenr 274877906944)
BTRFS RAID1 array with 2 500 GB hdds, no errors. This is the root filesystem, so there are 3 partitions on each drive: 1 = /boot (ext4), 2 = / (btrfs), 3 (swap)
/boot is ext4 because upgrading the ...
3
votes
1
answer
3k
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Fixing missing superblocks on both RAID1 disks using mdadm
My RAID1 array was working fine at /dev/md128 but seems to have completely disappeared after a reboot, with mdadm reporting both disks are missing superblocks. My question is how to fix this?
...
3
votes
2
answers
5k
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Creating disk device in a file
I'm trying to create disk device in a file with:
dd if=/dev/zero of=file.img bs=516096 count=1000
sudo losetup /dev/loop0 file.img
(echo n; echo p; echo 1; echo ""; echo ""; echo w;) | sudo fdisk -u -...
3
votes
2
answers
731
views
List what each sd is
On Linux I know that sda, sdb, and sdh are hard drives, but I don't know what is sdc, sdd, sde, sdf and sdg are. Some of them are (I think) empty and some of them, the kernel tries to make them ...
3
votes
3
answers
6k
views
How can I identify the filesystem/partition type
My hard drive got corrupted at some point after mounting an mtpfs system. I would ask how to fix that, but I'm not confident about the partition and file system types.
My OS is new Fedora Core 23, ...
3
votes
1
answer
4k
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All my superblocks are corrupt!
I am having a problem with my ubuntu ext3 filesystem. I can't boot from it or mount the volume when running live CD.
When I try e2fsck I get: "Bad magic number in super-block while trying to open /...
3
votes
1
answer
4k
views
Internal disk failed with bad superblock, how to fix? [closed]
NOTE: The operating system I'm using is on a separate disk (/dev/sdb).
I tried to mount my old root partition (/dev/sda12) as usual with the following command:
sudo mount /dev/sda12 /mnt
However, ...
3
votes
1
answer
2k
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Relation between "Block Size"and "Upper Limits" in ext2
A similar looking question asks for the reason why the upper file limit could be 2 TB in ext2. I am trying to understand but the Documentation on ext2 but find this hard. Please correct me if I'm ...
2
votes
1
answer
2k
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Superblock replicas in ext4
I am trying to find the association between block groups and superblocks in an ext4 filesystem
I was unable to find much of documentation online, except this link that hints that
Because of the ...
2
votes
2
answers
1k
views
mdadm metadata: should i take precautions to prevent superblock overwrite?
Situation:
I'm creating a new RAID1 array using mdadm.
I won't be using additional layers, such as LVM or dm-crypt.
I've noticed that metadata version 1.2 is now the default. I understand it's the ...
2
votes
1
answer
1k
views
mdadm + lvm2: destroyed all superblocks accidentally
I accidentally overwrote all my RAID1 superblocks with garbage. I think this happened because I ALT-CTRL-DEL booted when the Ubuntu had put me in some kind of hard disk recovery mode. My display wasn'...
2
votes
1
answer
3k
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Unable to mount /home/ partition after reinstalling grub after reinstalling windows 7
I've reinstall windows 7 on it's asignated partition and, as usually, it override the MBR with it's own stuff and, thus, it was not possible to boot to my ubuntu 12.04 partition.
I followed the step ...
2
votes
1
answer
8k
views
How can I view the superblock of an XFS partition?
I know that EXT superblock information can be found using dumpe2fs -h /dev/sda1, but what is the XFS equivalent of this? The best I have found so far is xfs_info /dev/sda1, but this doesn't seem to ...
2
votes
1
answer
3k
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Filesystem: How to find block of file represented by inode? [closed]
I am writing a file system for my operating system and am doing research on existing file systems before I start designing my own. I came across some slides about the System Five File System and am ...
2
votes
1
answer
3k
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Physical volumes, logical volumes, superblocks gone... how to boot?
A story fairly similar to this one happened to me yesterday.
Update:
My only hard drive /dev/sda was originally partitioned this way:
Device Boot Start End Blocks Id System
/dev/...
2
votes
2
answers
677
views
Rebuilding directory tree (and/or inodes)
Problem
My Armbian based Orange Pi webserver crashed (probably because of a power loss). I thought it would be fine since ext4 is more resilient and it usually has been in the past, but for some ...
2
votes
1
answer
3k
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EXT4 app2sd link2sd partition repair with bad superblock . Partition cannot be mounted on Android but will mount RW w/ su on Linux Live
I have a 128gb micro sd formatted as ext4 10gb for app2sd 2nd ext4 partition ( p2 ) on my Android 6 phone . All my apps ( 80%) stay on that ext4 partition . Now app2sd cant load this partition - "...
2
votes
0
answers
217
views
Raid can be assembled but not mounted, issue is with the superblock
I moved tow drives which where mounted in a raid1 to another to a new system to be mounted there. One drive was detected instantly, the other one had issues with the super blocks.
After reading Kevin ...
2
votes
1
answer
169
views
What is the most efficient way to search a block device for valid (filesystem) superblocks?
I have a block device that contains some valid filesystem (including the main and backup superblocks) at some unknown offset with some unknown block size. In my case I happen to know that it's an ext4 ...
2
votes
0
answers
463
views
Why do my software RAID1 superblocks keep getting corrupted and how can I prevent this?
How might I be repeatedly corrupting my superblocks on RAID1
I have had two occasions in the past six months of RAID1 root arrays becoming unusable because of problems with the superblock. ...
2
votes
1
answer
293
views
How to recover when ext4 superblock's inode count is reset to 0
We tried to resize a 15TB ext4 partition to 16TB and accidentally managed to hit an old (and fixed in newer releases) off-by-one bug of ext4_resize_fs() which causes inode count to reset to 0 thanks ...
2
votes
0
answers
1k
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fsck fails frequently(after each 3-4 boots)
I have triple boot System(Ubuntu,Kali,Win7) and I mostly use Kali
linux(4.6.0-kali1-amd64). After each 3 or 4 successful boots i get this
error ->
fsck.ext4: Superblock checksum does not match ...
2
votes
1
answer
3k
views
Short read while trying to open /dev/sda2
I just resized a .vdi from my host from 15.5G to 120G. I tried to resize the partition from the guest (ubuntu server) using resize2fs
root@ubuntu:~# sudo resize2fs /dev/sda2 115G
resize2fs 1.42.13 (...
2
votes
0
answers
3k
views
Superblock corruption on every boot
I have a Linux Mint 12 install on my laptop. Yesterday I powered it off like I always do and this morning when I started it I was greeted by an error screen.
(Translated from Swedish)
Fatal errors ...
1
vote
1
answer
194
views
Probabilistic (~50%) error on boot regarding "wrong fs type, bad option, bad superblock...missing codepage or helper program, or other error"
I've found a ton of posts on the internet regarding this error:
wrong fs type, bad option, bad superblock on /dev/xxx,missing codepage or helper program, or other error
Yet I have never found any case ...
1
vote
1
answer
766
views
How does the OS access files stored on the hard disk?
I know the first thing the OS accesses on the harddisk is the superblock.
But then what?
1
vote
1
answer
14k
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How to fix bad magic number - Superblock on Linux
I'm running a dual boot system with Windows 7 and Puppy Linux Ubuntu based "Bionic" installed on a separate partition of my main drive.
Completely separate from that I have a 1TB Western Digital ...
1
vote
1
answer
251
views
Unix ext2 superblock - file system creation date
I am trying to find the creation date on an ext2 file system. I seem to get a current date using dumpe2fs.
The problem is that the original ext2 superblock specification does not contain such ...
1
vote
1
answer
609
views
All superblocks corrupt, mismatched start sector on extended and logical partitions
While running Linux Mint 19 Cinnamon normally, the drive went into lockdown mode preventing disk writes indicating possible corruption. Upon shutdown and reboot I was met with ACPI errors.
Following ...
1
vote
1
answer
1k
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Manually backup superblock - how to & does it make sense?
Background
The first block of an ext4 filesystem is called the superblock - it contains essential metadata. There are backup copies of the superblock scattered throughout the filesystem; they can be ...
1
vote
1
answer
3k
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An existing mdadm RAID5 is not mounting, Either a problem drive or Superblock
I have 4 x 3TB NAS setup as RAID5 which has been working great for almost a year.
After a recent abrupt shutdown (had to hit the power button) the RAID will no longer mount on boot up.
I've run:
...
1
vote
1
answer
1k
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e2fsck giving some error
I am playing with LVM and while doing lvreduce. I now get this error:
[root@localhost raja]# e2fsck -f /dev/vg1/lvol2
e2fsck 1.41.12 (17-May-2010)
e2fsck: Superblock invalid, trying backup blocks...
...
1
vote
2
answers
555
views
Are Superblock and Master File Tables the same thing?
What is the difference between a superblock and a Master File Table (MFT)? Both seem to be tables that keep track of files within a filesystem, but are there other differences? The only difference I ...
1
vote
1
answer
1k
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Bad magic number in super-block: dm-crypt device
I have a device that is encrypted using dm-crypt. This is a mini SD card that I use on my laptop.
I've had some issues with my laptop freezing recently, and in the journal these messages come up:
...
1
vote
1
answer
1k
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bad magic number in superblock
I need to restore a broken partition superblock, so I get my list of backuped superblocks with :
sudo mke2fs -n /dev/sdd1
And I would like to know if when choosing the one to restore, if this is ...
1
vote
1
answer
2k
views
Recovering from bad superblock on external drive
read a few similar questions/posts and tried the solutions, still stuck. My scenario is simple, external ext4 drive was powered off (via cat) while operating, and failed to mount on boot. As I dug ...
1
vote
0
answers
919
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How did my ext3 superblocks get so messed up? And how to fix them?
I've recently found an old external hard disk and I have no idea what's on it. There was only one partition, encrypted with dm-crypt. Luckily I still remembered some of the passphrases that I used ...